This invention relates to a technology for diagnosing a failure based on a measurement value obtained by a power collector in a photovoltaic power generation system including a large number of photovoltaic cell modules.
Regarding a failure diagnosis for a photovoltaic power generation system, there exist technologies disclosed in JP 2011-187807 A and JP 2015-136233 A.
The following photovoltaic power generation system is disclosed in JP 2011-187807 A. Specifically, the photovoltaic power generation system includes a plurality of photovoltaic cell strings 8, each being formed by coupling in series photovoltaic cell modules 1, each being configured to generate DC power by light irradiation, and a junction box 2 to which the DC power generated by each of the plurality of photovoltaic cell strings is input. The junction box includes: a plurality of current detectors 10, each being configured to detect a total current value obtained by adding positive values being currents flowing through some of the photovoltaic cell strings and negative values being currents flowing through the remaining photovoltaic cell strings; a measurement apparatus 11 configured to measure the total current value detected by the current detector for each of the current detectors; and a data transmission apparatus 12 configured to transmit the current values measured by the measurement apparatus.
The following photovoltaic power generation system is disclosed in JP 2015-136233 A. Specifically, the photovoltaic power generation system includes: a photovoltaic cell string formed by coupling a plurality of photovoltaic cell modules; a junction box to which a plurality of the photovoltaic cell strings are coupled; a power collection apparatus configured to collect power of the junction box; a plurality of current detectors provided to the junction box and/or the power collection apparatus, each being configured to detect a current value per input unit; and a temperature detector configured to detect a temperature of an atmosphere in which the current detectors are provided. The current values detected by the current detectors are corrected based on the temperature detected by the temperature detector.